The immune system has the task of distinguishing between self and non-self. The mucosal immune system, present along the respiratory, gastrointestinal and genitourinary tracts, has the additional burden of coexisting with an abundance of bacteria and innocuous antigens, such as food, airborne antigens or the commensally bacterial flora. A key feature of the mucosal immune system is its ability to remain tolerant to these antigens while retaining the capacity to repel pathogens effectively. Introduction of antigen systemically, whether by injection or injury, leads to local infiltration of inflammatory cells and specific immunoglobulin production. By contrast, antigens introduced at mucosal surfaces, such as the gastrointestinal and genitourinary tracts, elicit active inhibition of the immune response to those antigens systemically. The specific induction of these regulated responses by administration of antigen through the gastrointestinal tract is known as oral tolerance. Oral administration of antigen can lead to systemic unresponsiveness and is an attractive alternative to immunosuppressive medical inventions that have undesirable side-effects (such as steroids). The invention lies in particular in the field of low-dose tolerance, obtained by continued exposure to low doses of antigen. Tolerance inductions via the mucosa have been proposed as a treatment strategy against autoimmune, allergic and inflammatory diseases.